Venus Williams shakes hand with Victoria Azarenka after their women's singles match at the Pan Pacific Open in Tokyo. Photo: Reuters
Australia's Sam Stosur blasted Japan's 42-year-old Kimiko Date-Krumm in straight sets on Tuesday to reach the last 16 of the Pan Pacific Open in Tokyo.
Meanwhile, former world No.1 Venus Williams overpowered ailing top seed Victoria Azarenka 6-2, 6-4 with ruthless efficiency join Stosur in the final 16.
Big-hitting Stosur, the 2011 US Open champion, didn't have it all her way with the home crowd willing Date-Krumm to produce an upset.
Samantha Stosur in action during her women's singles second-round match against Kimiko Date-Krumm. Photo: Getty Images
"I hung in as best I could but she played aggressively on the big points and didn't really show any weaknesses," said the 63rd-ranked Date-Krumm, who reached a career-high fourth in the world back in 1995.
"I'm disappointed to lose but I moved pretty well so the glass is half full."
Williams, the seven-times grand slam champion, showed glimpses of her gunslinging best against a grimacing Azerenka.
"I've sat through two US Open finals between her and Serena and you could tell from the first game she wasn't herself," Williams told reporters.
"It was definitely hard to concentrate because you sort of feel bad. I don't know what was bothering her but I just hope she feels better."
Azarenka, beaten by Serena Williams in the US Open final earlier this month in a repeat of the 2012 championship match in New York, had a large fan brought courtside to try to cool off at changeovers.
But such was her obvious discomfort she failed to threaten Williams. The 24-year-old Belarusian threw several tantrums as she repeatedly wafted shots off target or into the net.
"I haven't been able to practise for three days and I didn't sleep at all last night," said Azarenka. "I felt hot, then cold.
"Maybe I ate something bad but it's been getting worse," added the world number two, who complained of having eaten some bad sushi after a quarter-final exit from the $US2.3 million ($A2.45 million) event last year.
"You can't play at 20 per cent against a top player - it just doesn't work that way."
Williams completed her third victory in three meetings between the pair with a second serve.
"I'm getting better every tournament," said Williams, currently ranked a lowly 63rd in the world after two years of illness and injury problems. "I've had my issues, to say the least, but it's given me an unreal amount of character."
In other matches, Russia's Svetlana Kuznetsova, twice a grand slam singles champion, upset third seed Sara Errani of Italy, registering a 6-4, 6-4 win to reach the third round.
Sixth seed Jelena Jankovic brushed aside Japan's Ayumi Morita 6-4, 6-1 to advance. Another Serbian former world No.1, Ana Ivanovic thrashed Ukraine's Elina Svitolina 6-3, 6-0 to set up a meeting with fifth seed Angelique Kerber of Germany.
Canada's Eugenie Bouchard pulled off a surprise 5-7, 7-6, 6-3 victory over ninth-seeded Sloane Stephens, whose fellow American Madison Keys fared far better with a mature display in a 7-5, 6-2 victory over China's Peng Shuai that belied her tender age of 18.